Carton flap sealing

ABSTRACT

A hollow member arranged to apply heated air to heat-sealable surfaces of a pair of carton flaps folded to form an acute angle comprises an elongate chamber, preferably of generally triangular cross-section, which is connectable through a valve with a source of heated air. A nozzle extends from one corner of the chamber to extend between the pair of flaps and the nozzle has the end thereof remote from the chamber closed by a closure member which forms one side of opposed slots which extend lengthwise of the nozzle to direct heated air on to mating areas of the carton flaps. The closure member causes air to be deflected through the slots at substantially equal flow rates.

llnited States Patent [191 Oakley et al.

[ CARTON FLAP SEALING [76] Inventors: John Richard Oakley, 87

Churchward Ave.; Shaun Kearns, 7 Duchess Way, both of Swindon, England [22] Filed: Feb. 9, 1972 [21] Appl. No.: 224,888

[30] Foreign Application Priority Data Feb. 12, 1971 Great Britain 4,579/71 [52] U.S. Cl 53/375, 93/363, 156/282 [51] Int. Cl B65b 7/20 [58] Field of Search 53/375, 376; 93/36, 93/363, 52; 156/282, 497, 498, 499

[56] References Cited UNITED STATES PATENTS 3,610,114 10/1971 Kaminsky 53/375 X 3,535,987 10/1970 Schafer et a1 156/282 X 3,471,995 10/1969 Rogers 53/375 X [451 Aug. 14, 1973 3,309,841 3/1967 Egleston et a]. 53/375 X 3,249,024 5/1966 Shiu 53/375 UX Primary Examiner-Andrew R. .luhasz Assistant Examiner-W. D. Bray Attorney-Charles E. Brown et al.

[57] ABSTRACT A hollow member arranged to apply heated air to heatsealable surfaces of a pair of carton flaps folded to form an acute angle comprises an elongate chamber, preferably of generally triangular cross-section, which is connectable through a valve with a source of heated air. A nozzle extends from one corner of the chamber to extend between the pair of flaps and the nozzle has the end thereof remote from the chamber closed by a closure member which forms one side of opposed slots which extend lengthwise of the nozzle to direct heated air on to mating areas of the carton flaps. The closure member causes air to be deflected through the slots at substantially equal flow rates.

10 Claims, 5 Drawing Figures 4 5 /0 f g 9 Q 20 ///7 I l j J 5 /9- Patented Aug. 14, 1973 4 Sheets-Sheet 1 Patented Aug. 14, 1973 4 Sheets-Sheet 2 Patented Aug. 14, 1973 3,751,876

4 Sheets-Sheet 5 CARTON FLAP SEALING BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to improvements in sealing cartons and in particular to the sealing of cartons of the kind having underlying and overlying closure flaps secured one to the other by heat-sealable material ap plied to a mating area of one, or each, of each pair of said closure flaps. The heat-scalable material may be polyethylene, a polyethylene/wax mixture, or other thermoplastics material.

2. Description of the Prior Art It has been proposed, for example in U.S. Pat. No. 3,555,780, to effect softening of the heat-scalable material by folding one closure flap to a position at which the two closure flaps form an acute angle one with the other and while the flaps are so folded to move the carton past apparatus which includes a tubular member a part of which is located between the two flaps and which is provided with perforations from which heated air is directed on to the flaps to effect softening of the heat-scalable material prior to the flaps being folded one against the other and pressed to effect sealing of the flaps the one to the other. With such devices it is necessary to provide means to ensure that should the machine be stopped cartons then located for treatment by heated air do not become scorched and with apparatus of the kind proposed heretofore this is effected by swinging the tubular member away from the path of the cartons. It has also been proposed in U.S. Pat. No. 3,471,995 in connection with a perforated tubular member for applying heated air to a closure flap disposed substantially at right-angles to the flap to which it is to be secured to prevent carton scorching on stopping of the machine by interposing between the tubular member and the source of heated air a valve which includes a piston movable between two positions thereof. In one of such positions the piston permits the flow of heated air to the perforated tubular member and in the other position, to which it is moved when the machine is stopped, the piston causes the heated air to be passed out of an exhaust tube.

It is a main object .of the invention to provide an improved form of nozzle for use with apparatus for applying heated air to closure flaps which are folded to form an acute angle one with the other and which is capable of effecting the desired heating at a linear speed of a conveyor which is at least 50 percent higher than has been found possible when using tubular members provided with perforations thus resulting in the sealing of more cartons per minute than has been found possible with the known forms of apparatus.

A further object of the invention is to provide an apparatus for sealing cartons which apparatus embodies the improved nozzle and requires less frequent servicing than the known forms of apparatus in which the perforations in the tubular members require frequent cleaning and unblocking.

A still further object of the invention is to provide an apparatus for sealing cartons which embodies the improved nozzle and requires no change parts in order to permit the apparatus to effect closing and sealing of like cartons of different sizes, in particular like cartons of different heights.

SUMMARY According to the invention heated air is applied to heat-sealable surfaces of a pair of carton flaps folded to form an acute angle relative one to the other by a hollow member which comprises an elongate chamber connectable through a valve with a source of heated air. A nozzle extends lengthwise of and outwards from the chamber for location between the closure flaps and 0 the end of the nozzle remote from the chamber is closed by a closure member. The nozzle is provided with opposed slots which extend lengthwise of the nozzle and have a width selected to direct heated air on to predetermined mating areas of the closure flaps. One longitudinal side of each slot is defined by the closure member so that heated air is deflected from the nozzle and through the slots at substantially equal mass flow rates.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagrammatic plan of apparatus for applying heated air to heat-scalable surfaces of a pair of carton flaps folded to form an acute angle relative one to the other,

FIG. 2 is a partially exploded perspective view of a part of FIG. 1,

FIG. 3 is a section illustrating the mode of operation of the apparatus, 1

FIG. 4 is a partially exploded perspective view of a modified form of the apparatus of FIG. 2, and

FIG. 5 is a section illustrating the mode of operation of the apparatus of FIG. 4.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, pusher elements 1 carried by endless conveyor means, shown as continuously movable endless chains 2, are moved in succession past plough-type first folder elements 3 which fold closure flaps 4, FIG. 3, into positions in which they form acute angles with closure flaps 5 to which they are to be heatsealed by heat-sealable material applied to the respective closure flaps. The cartons with the flaps so arranged are passed between hollow members, described below, which extend lengthwise of the path of the cartons and are arranged to direct heated air on to predetermined mating areas of the flaps to effect softening of the heat-sealable material, following which the cartons are moved by the pusher elements 1 past second plough-type folder elements 6 which, in known manner, press the closure flaps 4 against the flaps 5 to effect heat-sealing of the one to the other.

Each hollow member consists of an elongate chamber 7 which includes a nozzle 8 which extends lengthwise of and outwards from the chamber 7 for location between the closure flaps 4, 5 as shown in FIG. 3. The nozzle 8 is provided with laterally opposed slots 9, FIG. 3, which extend lengthwise of the noule and have a width selected to direct heated air on to predetermined mating areas of the closure flaps 4, 5. The end of the nozzle 8 remote from the chamber 7 is closed by a cover member 10 which defines one longitudinal side of each slot 9 and deflects heated air from the nozzle 8 and through the slots 9 at substantially equal mass flow rates. It will be understood that the closed end of the nozzle may consist of a closure cast to be unitary with the nozzle 8 and chamber 7. The cover member may, however, be a member made separately from but which is secured to the remote end of the nozzle. The chamber 7 is of linear cross-section and the nozzle 8 extends outwards from a comer of the chamber 7 and in the embodiment illustrated in the drawings the chamber is of generally triangular cross-section so that heated air is directed by converging sides of the chamber into the nozzle.

The chamber 7 is connected with a source 11, FIG. 2, of heated air through a valve housing 12 which includes an inlet tube 13 connected with the chamber 7 and an exhaust tube 14. A piston 15 is slidable in the valve housing 12 and is provided with an opening 16, FIG. 2, which extends through the piston and with a recess 17 formed by a flat portion milled in the piston. An actuator 18, FIG. 1, is engaged in notches 19 in the outer end of the piston 15 and is arranged to effect axial sliding movement of the piston on starting and stopping of the machine. During running of the machine the opening 16 is aligned with the inlet tube 13 to permit the passage of heated air into the inlet tube and chamber 7 to nozzle 8, and the exhaust tube 14 is obturated by the piston. On stopping of the machine the actuator 18 moves the piston axially, to the right as viewed in FIG. 1, so that the piston obturates the inlet tube 13 and the recess 17 forms with the valve housing a passage through which heated air from the source 11 passes through the exhaust tube 14.

While the cartons are being moved between and past the nozzles 8, FIG. 1, the bottom of the carton rests on water-cooled guides 19, FIG. 3, provided with vertical guides 20 which retain the closure flaps 5 in the vertical position. Further water-cooled guides 21 retain the closure flaps 4 angularly spaced from the flaps 5 as shown in FIG. 3. The arrangement is such that, as indicated in accommodate cartons similar to the cartons 3 but of greater height.

The modified embodiment of the apparatus illustrated in FIGS. 4 and 5 is similar to that described above but the chamber 7 has secured thereto a secondary chamber 22 which extends lengthwise of the chamber 7. In this embodiment the exhaust tube 14 is connected with the secondary chamber 22 and an outlet tube 23, FIG. 4, extends from the auxiliary chamber 22. With this arrangement, when the machine is stopped the diverted heated air by passing through the auxiliary chamber 22 maintains the temperature of the chamber 7 and the nozzle 8 at such a temperature that instant restarting can be carried out. This is an advantage when the machine operates at very high speeds because it is not necessary to run the machine without cartons for a period of time sufficient to ensure that the nozzle will be reheated to a temperature which will ensure effcient softening of the heat-sealable material and thus satisfactory sealing of cartons. Further, with this embodiment it is possible to attain adequate heating of the nozzle before initial starting-up of the machine.

When using machines fitted with apparatus according to the invention it has been found possible to increase the linear speed, when using one known kind of heat-scalable material on the carton flaps, to 200 feet per minute as compared with a machine using a perforated tubular member and which could be run with like cartons at only 100 to 120 feet per minute. With cartons provided with other forms of heat-scalable material the comparative results were as follows:

Machine with apparatus Machine with peraccording to the forated tubular invention members 300 feet per minute 180 feet per minute 250 I30 300 200 200 200 l 10 Thus it will be seen that by using apparatus according to the invention it is possible to run carton closing and sealing machines at linear speeds at least 50 percent higher than that at which the same cartons can be satisfactorily closed and sealed by machines provided with perforated tubular members.

We claim:

1. A hollow member for applying heated air to heatsealable surfaces of a pair of carton flaps folded to form an acute angle relative one to the other, said hollow member comprising an elongate chamber connectable through a valve with a source of heated air, a nozzle extending lengthwise of and outwards from the chamber for location between the closure flaps, a closure member closing the end of the nozzle remote from the chamber, and opposed slots extending lengthwise of the nozzle and having a width selected to direct heated air on to predetermined mating areas of the closure flaps, one longitudinal side of each slot being defined by said closure member to deflect heated air from the nozzle and through the slots at substantially equal mass flow rates.

2. A hollow member according to claim 1, wherein the chamber is of linear cross-section and the nozzle extends outwards from a corner of the chamber.

3. A hollow member according to claim 2, wherein the chamber is of generally triangular cross-section.

4. A hollow member according to claim 1, in combination with a valve comprising a valve housing having an inlet tube connected with the elongate chamber, an exhaust tube opening from the housing, and a piston slidable in the valve housing and so constructed that in one position thereof the piston permits the passage of heated air into the inlet tube and obturates the exhaust tube and in a second position thereof the piston obturates the inlet tube and directs heated air into the exhaust tube.

5. The combination according to claim 4, wherein a secondary chamber extends lengthwise of the elongate chamber, the exhaust tube is connected with the secondary chamber, and an outlet tube extends from the secondary chamber.

6. A hollow member according to claim 1 in combination with pusher elements carried by an endless conveyor, first folder elements located alongside the path of the conveyor and operable to fold a pair of carton flaps to the acute angle relationship, guide elements extending lengthwise of the path of the conveyor and operable to retain the pair of carton flaps in said angular relation thereof, said elongate chamber extending lengthwise of the path of the conveyor, said nozzle extending lengthwise of and into the path formed between a pair of closure flaps engaged by said guides, a valve housing connectable with a source of heated air and including an inlet tube connected to the elongate chamber, an exhaust tube opening from the housing, a piston slidable in the valve housing, piston-actuating means operable on starting and stopping of the conveyor respectively to move the piston to a position at which heated air can pass into the inlet tube and the exhaust tube is obturated and to a position at which chamber extends lengthwise of the elongate chamber, the exhaust tube is connected with the secondary chamber, and an outlet tube extends from the secondary chamber.

10. The combination of claim 8, wherein a secondary chamber extends lengthwise of the elongate chamber,

the exhaust tube is connected with the secondary chamber, and an outlet tube extends from the secondary chamber. 

1. A hollow member for applying heated air to heat-sealable surfaces of a pair of carton flaps folded to form an acute angle relative onE to the other, said hollow member comprising an elongate chamber connectable through a valve with a source of heated air, a nozzle extending lengthwise of and outwards from the chamber for location between the closure flaps, a closure member closing the end of the nozzle remote from the chamber, and opposed slots extending lengthwise of the nozzle and having a width selected to direct heated air on to predetermined mating areas of the closure flaps, one longitudinal side of each slot being defined by said closure member to deflect heated air from the nozzle and through the slots at substantially equal mass flow rates.
 2. A hollow member according to claim 1, wherein the chamber is of linear cross-section and the nozzle extends outwards from a corner of the chamber.
 3. A hollow member according to claim 2, wherein the chamber is of generally triangular cross-section.
 4. A hollow member according to claim 1, in combination with a valve comprising a valve housing having an inlet tube connected with the elongate chamber, an exhaust tube opening from the housing, and a piston slidable in the valve housing and so constructed that in one position thereof the piston permits the passage of heated air into the inlet tube and obturates the exhaust tube and in a second position thereof the piston obturates the inlet tube and directs heated air into the exhaust tube.
 5. The combination according to claim 4, wherein a secondary chamber extends lengthwise of the elongate chamber, the exhaust tube is connected with the secondary chamber, and an outlet tube extends from the secondary chamber.
 6. A hollow member according to claim 1 in combination with pusher elements carried by an endless conveyor, first folder elements located alongside the path of the conveyor and operable to fold a pair of carton flaps to the acute angle relationship, guide elements extending lengthwise of the path of the conveyor and operable to retain the pair of carton flaps in said angular relation thereof, said elongate chamber extending lengthwise of the path of the conveyor, said nozzle extending lengthwise of and into the path formed between a pair of closure flaps engaged by said guides, a valve housing connectable with a source of heated air and including an inlet tube connected to the elongate chamber, an exhaust tube opening from the housing, a piston slidable in the valve housing, piston-actuating means operable on starting and stopping of the conveyor respectively to move the piston to a position at which heated air can pass into the inlet tube and the exhaust tube is obturated and to a position at which heated air can pass into the exhaust tube and the inlet tube is obturated, and second folder elements operable to press the carton flaps into sealing relation one with the other.
 7. The combination of claim 6, wherein the chamber is of linear cross-section and the nozzle extends outwards from a corner of the chamber.
 8. The combination of claim 7, wherein the chamber is of generally triangular cross-section.
 9. The combination of claim 6, wherein a secondary chamber extends lengthwise of the elongate chamber, the exhaust tube is connected with the secondary chamber, and an outlet tube extends from the secondary chamber.
 10. The combination of claim 8, wherein a secondary chamber extends lengthwise of the elongate chamber, the exhaust tube is connected with the secondary chamber, and an outlet tube extends from the secondary chamber. 